A former nanny of missing British girl Madeleine McCann has criticised the initial investigation into the girl’s disappearance, and revealed the unforgettable devastation experienced by her parents.

The woman, who has not been named, was reportedly working at the Portuguese resort where Madeleine vanished on May 3, 2007 and had looked after her several times.

“She [Kate McCann] was crying, but almost in a catatonic state, and Gerry was very distressed. That’s the one thing I really remember from him, looking under the cars. I can’t forget that,” the woman told The Mirror.

“She [Kate] was pacing up and down. The worst possible thing had just happened to her.”

Kate and Gerry McCann. (AAP) ()

The young girl, then aged three, vanished while her parents were at dinner in Praia da Luz, while on holiday in southern Portugal. They dined less than 100m from where Maddie and her two-year-old twin siblings slept.

Maddie’s father checked on her at 9.05pm and found them sound asleep. Her mother checked again at 10pm, and Maddie was gone.

The nanny revealed staff started “looking in bins” for the child, which is when she realised the severity of the situation.

British police officers search an area of wasteland during a search for evidence of Madeleine McCann in the town of Praia da Luz, Portugal. (AAP) ()

“I know I didn’t step into that apartment but pretty much everybody else did. So, evidence gone, nothing. There was nobody there to say, ‘We need to lock this off now’,” she told the UK-based news organisation.

“That’s why police were trying to get everyone’s timelines, because they weren’t there.”

She claimed large portions of her original statement were cut out, missing key details and causing a “catastrophic” effect on the investigation.

In a case that has captured worldwide attention, with no answers as to the circumstances of Maddie’s disappearance, the woman insisted there was “no way” Kate and Gerry were responsible.

Kate and Gerry McCann, the parents of missing Madeleine McCann, who said they were disappointed after Portugal's highest court threw out their libel case against ex-detective Goncalo Amaral, who implicated them in their daughter's disappearance. (AAP) ()

“A, timings and B, where it was, their reactions, the whole thing. Not a chance,” she said.

The woman also claimed the resort was known to be dangerous, and that staff were told to carry “a rape whistle” and not go anywhere alone.

“It didn’t sound like a family resort to me,” she said.

The parent company of the resort, Mark Warner, cut all ties to Praia da Luz in 2015.